1. Field of the Invention
The present invention relates to vehicle occupant restraint cushions commonly called air bags and adapted to be rapidly inflated with gas in the event of a crash or vehicle accident. More particularly, the air bag of the present invention is formed from thin, strong, light, flexible sheet material cut into a single pattern on a flat piece of the sheet material and sewn or joined along cut edges to provide a desired shape when the bag is rapidly inflated for protecting an occupant in a motor vehicle or the like.
2. Background of the Prior Art
Air bag restraint cushions of various sizes, shapes and materials have been available for use in providing protective restraint to occupants of motor vehicles. In fabricating many of these air bags it has been common practice to utilize multiple pattern pieces of sheet material sewn or seamed together to provide a completed air bag having a selected shape to provide a safety cushion for a vehicle occupant when the bag is rapidly inflated. However, prior art air bags having multiple pattern pieces are often difficult to fabricate, are somewhat labor intensive and are relatively high in cost. Many times pattern pieces of the air bag are easily lost or misplaced temporarily during the fabrication because of small size or large numbers of patterns for a single air bag. Sometimes pattern pieces are installed improperly in reverse order or backward orientation so that a relatively higher rate of rejects is common. Also, when a greater number of separate pattern pieces of sheet material having different diverse shapes are needed, inventory problems result and production rate is slowed.
Technicians and air bag fabricators often complain about prior art air bags being too hard to sew and prone to mismatching and misalignment of parts, sewing parts inside out, starting sewing in the wrong place, sewing the wrong parts together, etc.
When single piece air bags are provided in U.S. Pat. Nos. 3,810,654; 4,006,918; 4,169,613; 4,181,325; 4,988,118; 4,988,119; a desired final inflated shape is not always obtained that will provide maximum protection for a vehicle occupant. U.S. Pat. Nos. 5,044,663 and 4,842,300 disclose air bags having internal restraints or tethers for providing final shaping to an inflated air bag and these straps or tethers must be stitched in proper places within the air bag which complicates the fabrication thereof.